This invention relates to plastic display packages commonly designated blister packages, in which a plastic blister receptacle is secured to a generally flat backing member. In particular, this invention relates to such a package having means for easily tearing the plastic blister receptacle for gaining access to the contents of the package.
Plastic blister packages, also known as bubble packages, have been in long and extensive use for packaging and display of a wide variety of products. The package is composed of two primary components, a stiff backing, usually of cardboard, and a thermoformed blister receptacle having a peripheral flange which is bonded in some manner to the backing. The blister receptacle is shaped to fit over and cover articles that are to be contained within the package. It is usually formed of transparent plastic film so that the contents of the package may be viewed.
While such blister packages are relatively inexpensive, gaining access to the contents has proven quite difficult. The plastic blister is almost impossible to open wihout a sharp knife to cut into the plastic material and remove at least a sufficient part of the blister as to make it possible to remove the contents. The edge of the plastic blister is extremely difficult to tear manually, and normally the plastic material remains intact. If the backing is cardboard, the backing is, on occasion, perforated so that the contents may be removed through the cardboard backing. Often the perforations are inadequate to permit access to the contents of the package without some object to assist tearing of the backing along the perforation. If the perforation is too pronounced, during shipping and handling, the package can inadvertently be opened. Thus, perforation of the backing has found some utility, although limited.
Other suggestions for gaining entry to the blister receptacle have been made. For example, U.S. Pat. Nos. 4,119,203; 4,210,246; 4,266,666 and 3,942,690 has suggested various structures in which the blister is bodily separated or removed from the backing. The blister receptacle itself is not cut or torn during the removal process. U.S. Pat. No. 4,191,293 is similar to these patents, and also provides a separate tab to help remove the blister from its backing. Again, the blister is not torn or cut.
U.S. Pat. No. 2,793,745 discloses a package composed of a plastic blister secured to a backing. A tab is provided to permit rendering of the plastic material of the blister along a pre-formed score line. While the plastic of the blister is separated, there is no means in this patent of providing a starting point of weakness to initiate tearing along the score line.